Heterogeneous bonding of two different types of materials is becoming more common in optics and electronics for manufacturing integrated circuits (IC). The combination takes advantage of using materials with specialized and different properties to be combined into a single semiconductor for processing.
For example, a silicon on insulator (SOI) wafer provides low loss waveguide routing while a III-V compound semiconductor generates light efficiently for lasers, and absorbs light efficiently for modulators and detectors used in optical communication. The combination of these materials provides an ideal platform for creating photonic integrated circuits (PICs). Since the materials are dissimilar, the bond greatly influences the yield and process limitation in making these PICs. For example, in some applications, the goal is to make a highly integrated transmitter that is completely made through wafer-level scale processing.
For hybrid Si photonics, the shear strength of the bond between the compound semiconductor to the Si substrate has a great impact of device yield. Since the materials being bonded are different, separation and delamination between the materials is a common challenge to overcome. In addition, a multitude of acids are used in the fabrication of these devices to etch the compound semiconductor after bonding. However, the acids wick underneath the compound semiconductor following the Si channels and etch the bonding interface.